Intraoperative tumor bed boost with electrons in breast cancer of clinical stages I-III: Updated 10-years results
Menée à partir de données portant sur 770 patientes atteintes d'un cancer du sein de stade I à III traité par chirurgie conservatrice (durée médiane de suivi : 121 mois), cette étude évalue, du point de vue des taux de contrôle local et de survie à 10 ans, l'intérêt d'une radiothérapie par électrons de type boost ciblant le lit tumoral durant l'intervention chirurgicale
Purpose : To assess retrospectively the role of an anticipated intraoperative tumor bed boost with electrons (IOERT) during breast-conserving surgery (BCS) followed by conventional whole breast irradiation (WBI). Methods and Materials : An unselected cohort of 770 breast cancer patients of all risk types was analyzed in terms of local control (LC) and survival outcome. Patients were treated by BCS, IOERT of 10 Gy and WBI to total median doses of 54 Gy (1.6-2Gy). Patients were retrospectively analyzed for local control (LC), locoregional control (LRC), metastasis-free survival (MFS), overall survival (OS) and breast cancer specific survival (BCSS). Results : After a median FUP of 121 months (range 4-200), 21 (2.7%) in-breast recurrences (IBR) were observed, 108 (14%) patients died and 106 (14%) developed metastases. 10 year rates of LC, LRC, MFS, OS and BCSS amounted 97.2%, 96.5%, 86%, 85.7% and 93.2 %, respectively. In multivariate analysis, HER2+ and triple negative breast cancer suptype (TN) turned out to be significant negative predictors for IBR (HR, 15.02 and 12.87, respectively, p<0.05). Sorted by subtypes, 10y LC rates were observed in 98.7% (96.7-99.5) (luminal A), 98% (94-99.3) (luminal B), 87.9% (66.2-96) (HER2+) and 89% (76. 9-94.9) (TN), respectively. Conclusions : After 10 years, boost IOERT maintains high local control rates in any risk setting.